Jet aircraft utilize a variety of jet engines depending on the type of aircraft. Subsonic passenger jet aircraft are typically fitted with multiple fanjets, each of which includes a housing having a front intake, a rear nozzle and a central shaft rotatably mounted in the housing between the intake and nozzle. Multiple compressor fans are provided on the shaft inside the housing, and a combustion chamber is situated in the housing behind the compressor fans. In operation, air enters the fanjet through the intake of the housing. The compressor fans compress and expel the air into the combustion chamber. Jet fuel is injected into the combustion chamber and ignited with the compressed air, and the resultant expanding gases are violently ejected through the nozzle, propelling the aircraft forward.
Other types of aircraft, including military aircraft and other types of high-speed or supersonic aircraft, for example, commonly utilize ramjets, which have no compressor fans or other moving parts. Ramjets operate by utilizing compressed air that flows into the ramjet due to the aircraft moving forwardly at high speeds. Because fanjets utilize some of the burning fuel to rotate the compressor fans, ramjets are typically more fuel efficient at high speeds due to the lack of moving parts.